This invention relates to wood preservative and waterproofing compositions containing an amine oxide and an iodine containing biocide.
Mixtures of didecyldimethylammonium chloride (DDAC) and iodine containing biocides such as iodopropynylbutylcarbamate (IPBC), are currently used for treating wood to prevent the growth of stain causing fungi (see, e.g., U.S. Pat. No. 4,950,685). IPBC is known to be effective against fungi that cause structural and cosmetic damage to wood.
These mixtures are often distributed as concentrates. When diluted, the solutions frequently are characterized by poor phase and color stability, the IPBC often coming out of solution within a day or two after preparation. These solution also have low corrosion resistance. Furthermore, DDAC and IPBC compositions containing iron stain inhibitors typically have a low pH, making them less desirable for use in mills and other factories. A firer disadvantage of many of the prior art wood preservative compositions is that they contain halides, which are considered environmentally unfriendly.
Therefore, there is a need for iodine containing biocide compositions which have improved phase and color stability and corrosion resistance, and are able to form compositions containing iron stain inhibitors at higher pH.
Applicants have discovered that amine oxides enhance the performance of iodine-containing biocides as wood preservatives and provide waterproofing properties. The present invention provides a composition comprising an amine oxide and an iodine-containing biocide, particularly iodopropynyl butyl carbamate.
Another embodiment of the present invention is a method for preserving and/or waterproofing a wood substrate by impregnating the wood substrate with the composition.
Yet another embodiment is an article comprising a wood substrate treated with the composition of the present invention.
The composition of the invention has improved phase stability over prior art compositions and high resistance to color formation. The composition of the invention also has low corrosivity to metal components, including, but not limited to, steel components, such as those used in wood treatment systems. Compositions of the present invention which include iron stain inhibitors generally have higher pH than prior art iodine containing biocide containing compositions, allowing for safer handling of such compositions. Additionally, the amine oxide in the composition may impart waterproofing properties to the wood. Further, the composition of the present invention may be advantageously free of halide ions.
Examples of compounds which may be used as the iodopropynyl component of the invention are the fungicidally active iodoalkynyl derivatives. These include compounds derived from propyne or iodopropynyl alcohols, such as the esters, ethers, acetals, carbamates and carbonates and the iodopropynyl derivatives of pyrimidines, triazolinones, tetrazoles, triazinones, sulfamides, benzothiazoles, ammonium salts, carboxamides, hydroxamates, and ureas.
Preferred iodine containing biocides include 3-iodo-2 propynyl derivatives such as 3-iodo-2-propynyl butyl carbamate, 3-iodo-2-propynyl succinate and p-chlorophenyl-3-iodopropynyl formal; an iodo sulfone derivative, or triiodoallyl alcohol.
The iodopropynyl carbamate compounds, included within the broadly useful class of compounds, have the generic formula: 
wherein R is selected from the group consisting of hydrogen, and substituted and unsubstituted alkyl, aryl, and alkylaryl groups having from 1 to 20 carbon atoms; and q and z are independent integers from 1 to 3.
The iodopropynyl ester compounds are included within the broadly useful class of compounds having the generic formulas: 
wherein:
R1 and R2 are defined as R3 and R4 below or are joined to form a cycloalkyl, cycloalkenyl, aromatic or a heterocyclic ring containing an oxygen, nitrogen or sulfur atom or an alkoxy, amino, carboxyl, halo, hydroxyl, keto or a thiocarboxyl-substituted derivative thereof;
R3 and R4 are independently selected from (A) hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, a heterocyclic ring containing an oxygen, nitrogen or sulfur atom, alkoxy, amino, carboxyl, halo, hydroxyl, keto or a thiocarboxyl and (B) substituted derivatives of the alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and the heterocyclic ring wherein the substitutions are alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkoxy, amino, carboxyl, halo, hydroxyl, keto or a thiocarboxyl; y is 0 to 16; W may be a single bond, oxygen, NR5, or (CR6R7)p, wherein R5 is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl or a heterocyclic ring containing an oxygen, nitrogen or sulfur atom or a substituted derivative of alkyl, cycloalkyl, alkenyl, cycloalkenyl or aryl groups wherein the substitutions are alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkoxy, amino, carboxyl, halo, hydroxyl, keto, or a thiocarboxyl wherein R6 and R7 are defined as R3 and R4 above; and p is an integer from 1 to 12. The above definition of R5 includes, among other things, an aminoalkyl group.
The heterocyclic rings referred to in the above definitions may contain from 5 to 8 members, the alkyl or cycloalkyl groups from 1 to 18 atoms, the alkenyl or cycloalkenyl groups from 2 to 18 carbon atoms, and the aryl groups from 6 to 10 members. X is hydrogen or a salt-forming cation such as an alkali metal, an alkaline earth metal, ammonium, tertiary ammonium, a quaternary ammonium, a biguanide or a polybiguanide.
In formula III, when R1 and R2 are hydrogen, the compound is a maleate. When R1 and R2 are joined together to form part of a six membered aromatic ring the compound is a phthalate. In formula II, when R1, R2, R3, and R4 are hydrogen and W is a single bond, the compound is a succinate. When R1, R2, R3 and R4 are hydrogen and W is an oxygen, the compound is a diglycolate. Other compounds include the mono-iodopropynyl esters of anhydrides such as ethylenediamine tetraacetic dianhydride, 3,3-dimethylglutaric anhydride, S-acetylmercaptosuccinic anhydride, dichloromaleic anhydride, 2-dodecen-1-yl succinic anhydride and cis-5-norbornene-endo-2,3-dicarboxylic anhydride. Where hydrophilicity is desired, the sodium salts may be used because of their extremely high water solubility. Preferred carboxylic acid anhydrides include succinic, itaconic, phthalic, tetrachlorophthalic, and diglycolic anhydride. Such compounds are defined in U.S. Pat. No. 4,844,891 and 5,073,570.
More preferably the iodine containing biocide is 3-iodo-2-propynyl butyl carbamate (IPBC). The IPBC may be any grade of IPBC including, but not limited to, an essentially pure commercial grade IPBC in solid form and a commercially available 40% grade in a solvent.
The iodopropynyl compounds are also included within the class of compounds having the generic formula:
Ixe2x80x94Cxe2x89xa1Cxe2x80x94(CH2O2)2xe2x80x94R8
wherein R8 is benzyl or benzyl substituted with a methyl, methoxy, carboxyl, halogen or nitro group; preferably the compound is p-chlorophenyl-3- iodopropynyl formal.
The amine oxide may be a trialkylamine oxide; an alkylcyclicamine oxide; a dialkylpiperazine di-N-oxide; an alkyldi(poly(oxyalkylene))amine oxide; a dialkylbenzylamine oxide; a fatty acylamidopropyldimethylamine oxide; a diamine oxide; a triamine oxide; and any combination of any of the foregoing.
Preferred trialkylamine oxides have the formula R9R10R11Nxe2x86x92O, where R9 is a linear, branched, cyclic or any combination thereof C6 to C40 saturated or unsaturated group; and R10 and R11 independently are linear, branched, or any combination thereof C1 to C40 saturated or unsaturated groups. R9, R10, and R11 independently may be alkyl, alkenyl, or alkynyl groups; or may be replaced by other short chain alkyl or substituted alkyl groups, such as ethyl and hydroxyethyl. More preferably, R9 is a linear, branched, cyclic or any combination thereof C8 to C22 saturated or unsaturated group, such as coco, hydrogenated tallow, soya, decyl, and hexadecyl; and R10 and R11 independently are linear, branched, or any combination thereof C1 to C22 saturated or unsaturated groups, such as coco, hydrogenated tallow, soya, decyl, and hexadecyl.
A preferred trialkylamine oxide is a dialkylmethylamine oxide having the formula R9R10CH3Nxe2x86x92O, where R9 and R10 are defined as above. Another preferred trialkylamine oxide is an alkyldimethylamine oxide having the formula R9(CH3)2Nxe2x86x92O, where R9 is defined as above. Suitable alkyldimethylamine oxides include, but are not limited to, a C10alkyldimethylamine oxide, a C12-C14, alkyldimethylamine oxide, a C16-C18 alkyldimethylamine oxide, and any combination of any of the foregoing.
Preferred alkylcyclicamines oxide have the formula R12R13R14Nxe2x86x92O where R12 is defined as R9 above and R13 and R14 are linked to form a cyclic group. The cyclic group typically contains from about 4 to about 10 carbon atoms and may optionally contain oxygen, sulfur, nitrogen, or any combination of any of the foregoing. More preferred alkylcyclicamine oxides include, but are not limited to, an alkylmorpholine N-oxide, a dialkylpiperazine di-N-oxide, and any combination of any of the foregoing.
Preferred alkylmorpholine N-oxides have the formula 
where R15 is defined as R9 above.
Preferred dialkylpiperazine di-N-oxides have the formula 
where R16 is defined as R9 above and R17 is defined as R10 above.
Preferred alkyldi(poly(oxyalkylene))amine oxides have the formula 
where R18 is defined as R9 above; R19 and R20 independently are H or CH3; and m and n independently are integers from about 1 to about 10.
Preferred dialkylbenzylamine oxides have the formula R21R22R23Nxe2x86x92O, where R21 is defined as R9 above; R22 is defined as R10 above; and R23 is benzyl. More preferred dialkylbenzylamine oxides include, but are not limited to, alkylbenzylmethylamine oxides having the formula R21R23CH3Nxe2x86x92O where R21 and R23 are defined as above.
Preferred fatty acylamidopropyldimethylamine oxides have the formula 
where R24 is defined as R9 above.
Preferred diamine oxides have the formula 
where R25 is defined as R9 above; and m is an integer from about 1 to about 10.
Preferred triamine oxides have the formula 
where R26 is defined as R9 above; and m and n independently are integers from about 1 to about 10.
Long chain (C16 or greater) amine oxides, such as hexadecyldimTethylamine oxides, octadecyldimnethylamnine oxides and hydrogenated tallow amine oxides, are particularly preferable for imparting waterproofing properties to the composition. Short chain (C14 and shorter) amine oxides, such as decyldimethylamnine oxides, lauryldimethylamine oxides and tetradecyldimnethylamine oxides, aide in solubilizing the IPBC and long chain amine oxides, and are efficient stabilizers.
A blend of long chain and short chain amine oxides is also contemplated in one embodiment of the present invention. The long chain amine oxides may be blended with the short chain amine oxides in a ratio of about from about 1:10 to 10:1 in order to yield a clear and stable preservative solution as described herein upon dissolution of iodine containing biocide in the amine oxide solution. For example, in a preferred embodiment, a mixture of long chain (e.g., C16) and short chain (e.g., C12) amine oxides in a ratio of 5:2 provides the desired dissolution of iodine containing biocide to provide a clear and stable solution. The appropriate ratio of long to short chain amine oxides can be readily determined by those of skill in the art using methods provided herein to test solubility and stability of the solutions.
The composition may include a solvent, such as water and water miscible solvents, including, but not limited to, alcohols, such as ethanol, glycols, esters, ethers, polyethers, amines, and any combination of any of the foregoing.
The composition, when in concentrated form, preferably contains from about 20 to about 70% by weight, and preferably from about 30 to 65% by weight, of combined amine oxide and iodine containing biocide based upon 100% weight of total composition. The concentrate contains 0.01 to 1 parts of iodine containing biocide per part of amine oxide; and most preferably 0.05 to 0.5 parts of iodine containing biocide to 1 part amine oxide.
The concentrate may be diluted to a range of about 0.1 to 5% (total solids) for treating wood. Use dilutions of the composition typically comprise a biocidally effective amount of iodine containing biocide and a preservative enhancing and/or waterproofing effective amount of the amine oxide. Use dilutions preferably comprise from about 0.5 to about 2.0% by weight of amine oxide and from about 0.05 to about 0.2% by weight of iodine containing biocide based upon 100% weight of total composition. The composition of the invention has a weight ratio of iodine containing biocide to amine oxide of about 0.001:1, preferably 0.01:0.8.
Iron stain inhibitors, such as phosphonic acid derivatives, may be included in the composition. Suitable phosphonic acid derivatives include, but are not limited to, amino tri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), diethylenetriaminepenta(methylene-phosphonic acid), bis hexamethylene triamine phosphonic acid, and any combination of any of the foregoing. The iron stain inhibitor will be present in an amount of about 0.01 to 1%, preferably in an amount of about 0.05 to 0.5%, and most preferably in an amount of about 0.1 to 0.4%. Typically, the pH of the composition containing the iron stain inhibitor will be in the range of about 3.0 to7.0, and preferably about 3.8 to 5.2.
Other adjuvants may be included in the composition as known to one of ordinary skill in the art. Other biocides, fungicides and insecticides may be include in the composition.
The composition of the present invention is readily prepared by mixing iodine containing biocide, amine oxide, solvents, and adjuvants. The mixture may be heated and/or stirred to expedite mixing.
Another embodiment of the present invention is a method for preserving and/or waterproofing a wood substrate by contacting a wood substrate with the composition of the present invention. The composition may be applied by any wood treating method known to one of ordinary skill in the art including, but not limited to, brushing, dipping, soaking, vacuum impregnation (e.g., double vacuum technique), and pressure treatment using various cycles.